Balanced valve.



J. F. GILL.

BALANCED VALVE.

APPLICATION FILED 05c. 22. 1914.

Patented Sept. -12, 1916.

2 SHEETSSHEET I 7 @a@ we I. F. GILL.

BALANCED VALVE.

APPLICATION FILED pec.22,1914.

Patented Sept. 12, 1916.

2 SHEETS-SHEET 2.

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" sponding i it it J'ES FRANCIS GILL, 0F LIVERPOOL, ENGLAND.

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Application filed December 22, 1914; Serial No. 878,571.

To all whom it may concern:

Be it known that I, JAMES FRANCIS GI LL, a subject of the King of England, residing at 25 Castle street, Liverpool, England,

controlling the flow of fluid in pipes, of the kind having'a balance-pi'ston attached .to the valve wherein the equalization of pressure on the two sides of the combined valve and balance-piston is effected by the operation of a; pilot valve carried by the main valve spindle and 'having a limited movement relative to the main valve.

In most such valves as heretofore constructed when the pilot valve is opened to equalize the pressure, and until the pressure is equalized on both sides of the balancepiston, the main valve vibrates or chatters on its seat.

My invention is designed to obviate this defect and comprises novel features of construction and arrangement of the balancepiston and main valve hereinafter more fully described and set out in the claim.

The accompanying drawings illustrate two forms of construction suitable for steam valves, but I do not limit myself to these forms.

The same reference letters where they occur are used to denote the same or correparts in both figures.

InFigure 1 the main single-seated valve A operates on its seatingB which is fixed tightly into the body part 0. Screwed on to or otherwise suitably secured to the main valve A is the balance-piston D which slides in the cylinder E, this latter being provided with a ported end F and supported 'centrally in the body Oby the lip G. The

valve spindle H, passes through the stuffing box I and is provided atits lower end with a threaded portion on which is screwed an adjustable collar J with a lock-nut .K located in a chamber Q in the balance-piston D. The pilot valve L in this case is formed by an enlargement of the spindle H and is so positioned thereon as to come on to its seating M in the end F of the cylinder E after the main valve A has been closed. lVhen the pilot valve L is open, the space Specification of Letters Patent.

' main valve has been closed.

- Patented se t. i2, iaie.

above the balance-piston D communicates with the outlet side of the main valve by means of the ports P P.

In order to give the main valve a definite position on the spindle when the valve is open and to prevent chattering a spring is arranged so that it tends to force the main valve to its closed position. This spring becomes slightly compressed when the main valve shuts. The said spring S is located in a chamber Q'in the'balance-piston and is compressed between a flange on the adjustable collar J and the main valve A so that the valve is displaced relatively to the spindle. The limited co-axial relative motion between the spindle with its pilot valve and the main valve is provided-for by the position of the adjustable collar J with its lock-nut K. The valve spindle may be operated by any device, lever B, which insures that the pilot valve L will be forced on to its seat only after the The banking up of the pressure behind the balance piston D is permitted by the leakage due to the clearance between the such as the Weightedpiston and the cylinder E, which leakage is reduced by the use of periphery of the piston.

If desired piston rings may be provided for the piston and a leakage permitted by means of a hole drilled through the piston or through the cylinder. are that a leakage must be providedand the leakage orifice must obviously be smaller than thatprovided by the pilotvalve when grooves around the The main points it has its maximum openlng. When .the

pilot valve is shut the leakage permits the pressure on the balance-piston to mount up to that on the inlet side the main valve is now pressed firmly. on to its seating and the pilot valve prevents the escape of any of the steam which has passed the piston.

The action of the valve is as-follows :On first raising the lever R the main valve A is unaffected, but the pilot valve L lifts a limited amount and this permits the steam pressure,'which has accumulated above the balance-piston D to fall to that of the outof the valve so that 1 let side of the main valve. The main valve A-is then in equilibrium so that a further movement of the lever-R will cause it to open.

In the construction shown in Fig. 2 the action of the parts is precisely similar except that thepilot valve L now has its seating in themain valve A and communication between the effective side of the balancepiston D and the outlet side of the valve is established through ports P P in the balance=piston and mam valve, consequently the cylinder E requires no other cover than sage of steam suflicient to bank up the pres- 7 sure.

The valve spindle is shown operated by a handwheel and screw, but any other convenient form of operating gear'may be employed.

Iam aware that it has already been proposed to provide hydraulic valves having pilot valves with a spring which continually exerts a pressure on the main valve, tending to close it but in such valves the. force of the spring increases with the opening of the valve.

In my invention, on the contrary, the spring reacts directly between the main valve and the pilot valve so that when the pilot valve has made its limited co-axial movement the spring can exert no further force on the valve spindle and therefore on the main valve, consequently the main valve is balanced.

Having fully described my invention, what I claim and desire to secure by Letters Patent is A single-seated balanced valve comprising a valve casing, a valve seating and a cylindrical part in said casing, a main valve, a balance-piston on said valve and having a cavity therein, said valve and piston belng mounted to operate respectively on said seating and in said cylindrical part, a valve spindle capable of co-axial movement in relation to the balanced valve, a pilot valve on said spindle, an adjustable collar on said spindle, a spring mounted in the cavity in the balance-piston and re-acting between the main valve and the said adjustable collar,

and ports'communicating between the effective side of the balance-piston and the valve outlet when the pilot valve is open.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses this 3rd dayof December 1914.

JAMES FRANCIS GILL.

Witnesses:

JOHN N. CHALRORA, HAROLD HAssALL. 

